1. Field of the Invention
The present invention relates to a shaft drive device. The present invention relates to a shaft drive device that is suitable for driving a wheel of, for example, a vehicle such as a motorcycle.
2. Description of Background Art
In the past, for example, as disclosed in JP-A No. S62-18383, there has been known a shaft drive device where a shaft of a pinion gear (12) engaged with a ring gear (15) extends toward a power unit in a final gear case (10) that is provided in a power transmission system between an engine used as the power unit and a rear wheel, a spline is provided on the outer circumference of the shaft, a spline is provided on the inner circumference of a cylindrical portion of a pinion joint that forms a receiving portion of a joint provided at a rear end of a propeller shaft (8) for transmitting power from the power unit to the pinion gear (12), and the spline of the pinion joint and the spline of the pinion gear (12) are engaged with each other so that the pinion gear is spline-connected to the pinion joint (11).
Since the pinion gear and the pinion joint are spline-connected to each other in tie above-mentioned shaft drive device in the related art, the pinion gear and the pinion joint can slide relative to each other in the axial direction thereof.
For this reason, the device in the related art has had a problem in that noise or vibration caused by the sliding is generated.